I am curious how a young American nurse would have ever been captured on Kwajelein in the first place. Female nurses certainly wouldn't have been at the front during the invasion. My limited knowledge of the history of the place indicates the Japanese took what was German administrative control of the Marshal Islands after WWI.
Could be a garbled account, complicated by scuttlebutt.
May not have been American, or a nurse.
May have been an Australian, British or NZ woman taken in the occupation of other islands in the region, such as Tarawa.
These were occupied by Japan by expeditionary forces staging from the Marshall Islands bases IIRC.
http://en.wikipedia.org/wiki/Gilbert_and_Ellice_Islands
Louis Zamperini passed through the island as a prisoner along with his comrade.